Apps similar to ToolStack Folio include Obsidian, which has a free version. Other options are Joplin, Notesnook, Google Keep and Simplenote. There's no shortage of Note-taking Tools like ToolStack Folio, with more than 50 alternatives for Mac, Windows, Linux, Android and iPhone.
Native macOS Markdown reader and editor with Document, Split, and Source views, customizable themes, Finder and Quick Look integration, real-time file monitoring, broad Markdown support, and the ability to review external file changes. Free and MIT licensed.
United States
iA Writer is a pro tool for focused writing in Markdown, a simple formatting language. It offers features like Focus Mode, Style Check, Syntax Highlight, Wikilinks, and cross-platform compatibility.
Switzerland
Ulysses is a text editor for creative writers. Used by bloggers, poets, students and published novelists all over the world, it offers an integrated environment to brainstorm, draft, revise and even submit text on a professional level.
Germany
EU
Focus on your words not the interface. Quoll Writer is a writing application that helps you focus on your words. Clean and uncluttered. Feature rich. Features are where you would expect them to be.
Australia
As easy to use as a word document or bulleted list, and as powerful for finding, collecting, and connecting related ideas as a graph database. Collaborate with others in real time, or store all your data locally.
United States
novelWriter is a Markdown-like text editor designed for writing novels and larger projects of many smaller plain text documents. It uses its own flavor of Markdown that supports a meta data syntax for comments, synopsis and cross-referencing between files.
This program is a structured notetaking application based on GTK+ 3. Write your notes in instantly-formatted Markdown, organise them in a tree of folders that can be instantly navigated from within the program, and add hand-drawn notes by mouse, touchscreen or digitiser.
Apostrophe is a simple GNU/Linux Markdown editor built with the GTK+ framework.
United States
Offers fast, distraction-free note-taking via a high-performance editor with real-time Markdown, local-first storage, image support, Kanban task boards, intuitive drag-and-drop, keyboard shortcuts, configurable themes, fast search, and cross-platform access.
Israel
Vietnam
Silver Bullet is an extensible, open source, personal knowledge management system. Indeed, that’s fancy talk for “a note-taking app with links.” However, Silver Bullet goes a bit beyond just that.
United States
United States
